1. Field of the Invention
The present invention relates to an electronic component mounting package having a laminate structure of a plurality of ceramic layers, and to a package assembled substrate, which is an intermediate product thereof.
2. Description of Related Art
A light emitting device as shown in FIG. 12 has been conventionally known in which a light emitting element 11 such as an LED is mounted in a package 8 formed by laminating a plurality of ceramic layers (JP 2002-232017, A). The package 8 is provided with a cavity 81 for housing the light emitting element 11. A first land layer 8a and a second land layer 8b are formed with a conductive material such as silver on the bottom surface of the cavity 81. A power supply terminal (not shown) provided on the top surface of the light emitting element 11 is connected to the first land layer 8a via a wire 12, while a ground terminal (not shown) provided on the reverse surface of the light emitting element 11 is connected to the second land layer 8b. 
The package 8 has a mount surface 14 to be a joint surface when mounted on a mother board, defined on a side surface thereof parallel with the depth direction of the cavity 81. A pair of external electrodes 82, 82 for connecting the light emitting element 11 to an external circuit on the mother board are formed on the mount surface 14. The first land layer 8a and second land layer 8b are connected to the pair of external electrodes 82, 82 via a via hole (not shown).
The above-described light emitting device is mounted on the mother board with the mount surface 14 of the package 8 being opposed to a surface of the mother board, i.e., with the opening direction of the cavity 81 of the package 8 (light emitting direction of the light emitting element) being parallel with the mother board.
There has been known a specific structure of a pair of external electrodes to be formed on a package for the light emitting device as described above, in which, as shown in FIG. 13(a), FIG. 13(b) and FIG. 13(c), a through hole extending along the laminating direction of ceramic layers constituting a package 83 is provided at each end of a mount surface 14 of the package 83, and then a film of a conductive material such as silver is formed on the inner peripheral surface of the through hole to provide an external electrode 84.
However, in a mounting structure with the external electrode 84 shown in FIG. 13(a), FIG. 13(b) and FIG. 13(c), the area of the external electrode 84 exposed to the mount surface 14, i.e., mounting area is extremely small. Therefore, there has been a problem of the package 83 shifting during a process for mounting the light emitting device on a mother board with solder reflow.
Accordingly, as shown in FIG. 14(a), FIG. 14(b) and FIG. 14(c), it is possible to form a layer of a conductive material such as silver at each end of a package 85 across a mount surface 14 and a side surface perpendicular to the mount surface 14 to provide an external electrode 86 with an L-shaped cross section. According to a mounting structure with the external electrode 86, the area of the external electrode 86 exposed to the mount surface 14, i.e., mounting area can be formed sufficiently large. This can suppress a shift of the package 85 during solder reflow.
In a manufacturing process for the package 85 shown in FIG. 14(a), FIG. 14(b) and FIG. 14(c), a package assembled substrate with a plurality of packages to be cut out therefrom is produced, and thereafter the package assembled substrate is cut by a dicer. In this process, a conductive material such as silver to provide the external electrode 86 of each package 85 will also be cut together by a dicer. Therefore, there has been a problem of burrs or the like occurring on cut surfaces to provide a surface of the external electrode 86 with poor flatness.